The invention relates to an improvement to a commercially available sport card slitting machine known as the "Rollem Slip Stream" machine, and more particularly to a device and method for conveniently adjusting the relative locations or "timing" of a pair of notches in the lower blades of a first stage slitter assembly relative to leading and trailing edges of an advancing photo sheet.
Sport cards, such as baseball trading cards and the like, are very popular, and several major companies, including the present assignee, compete vigorously in this large market.
In the manufacture of sport cards, a large number of photographs of various individual athletes are printed on each of many large, single sheets of suitable paper (herein referred to as "photo sheets"). Each large photo sheet then is slit, first "horizontally" and then "vertically", to form a group or collection of individual sport cards which then are collated and packaged.
To this end, the sport card industry has used a card slitting machine called the "Rollem Slip Stream machine". The standard Rollem Slip Stream machine includes a first stage slitting assembly that is manufactured by Rollem, and is shown in FIG. 1. Various aspects of the Rollem Slip Stream machine are disclosed in U.S. Pat. No. 4,405,121 by Hill, issued Sep. 20, 1983 entitled "Cutting and Collating Sheets of Paper Cards, etc.", and incorporated herein by reference.
FIG. 1 herein shows a top view diagram of the Rollem Slip Stream machine 1. A large (typically 28 inches by 40 inches) photo sheet 40 is advanced along a first section 6, as indicated by arrow 3. A first stage slitting assembly 2 includes a lower blade assembly 15, 19 and an upper blade assembly 10, 18, as shown in FIG. 3. The prior art Rollem first stage slitting assembly 2 makes "interrupted cut" slits such as 41 in photo sheet 40, as shown in FIGS. 2 and 2A. The "interrupted cut" slits 41 are necessary to provide a leading edge margin 42A and a trailing edge margin 42B so that photo sheet 40 remains intact, allowing it to be advanced as a unit in direction and then at a right angle thereto in direction 5, to a second stage slitting assembly 14 and then, after the "horizontal" interrupted cut slits 41 are made, into a second section 7. In first stage slitting assembly 2, a number of individual "interrupted cut" slits 41 are made, each of which extends to within approximately 1/2 inch of the opposed leading and trailing edges of photo sheet 40, leaving leading and trailing edge margins 42A and 42B, respectively, that maintain "horizontally" slit photo sheet 40 intact so further advancing and "vertical" slitting of the entire photo sheet 40 is possible. The second stage slitting assembly 14 cuts a second set of "vertical" slits (not shown) that are perpendicular to the "horizontal" interrupted cut slits 41.
Referring to FIG. 3, the prior art Rollem Slip Stream first stage slitting assembly 2 includes a number of upper hub/blade assemblies 18 mounted on a single gear-driven upper shaft 10. Each hub/blade assembly 18 includes a thin, circular upper blade 12 secured by set screws (not shown) to a planar face of an upper hub 11. Set screws (not shown) secure the various upper hubs 11 to shaft 10, which is journaled in several stationary bearing assemblies (not shown).
Numeral 19 designates lower hub/blade assemblies of the standard Rollem first stage slitting assembly 2. Each lower hub/blade assembly 19 includes a thin circular blade 17 mounted on a hub 16, which in turn is mounted on a common gear-driven lower shaft 15. The drive of lower shaft 15 is "synchronized" with the drive of upper shaft 10 so that the cutting edge velocity of upper blade 12 is precisely the same as that of lower blade 17. As shown in FIGS. 3 and 4, the lower portion of each upper blade 12 and the upper portion of each lower blade 17 make contact in a "blade overlap" area. The upper blades 12 are urged against the corresponding lower blades 17 in the blade overlap area, as indicated by arrow 25 in FIG. 3. A sheet feeder 35 advances the leading edge of photo sheet 40 in the direction of arrow 34 in FIG. 4 in synchronization with the arrival of leading notch 17-1 in each of the lower blades 17 at the blade overlap area to determine the location of the leading end of each interrupted cut slit 41. When the trailing notch 17-2 of each lower blade 17 later arrives at the blade overlap area, it determines the location of the trailing end of each interrupted cut slit 41.
As shown in FIG. 3, a resilient 0-ring 30 is disposed in a mating groove in each of upper hubs 11. As photo sheet 40 is advanced between the upper hubs 11 and lower hubs 16, resilient O-ring 30 frictionally contacts the upper surface of photo sheet 40 and aids in advancing it between the upper and lower slitter blades 12 and 17. If the upper surface of photo sheet 40 is slippery because of the type of finish thereon, some slippage will occur between O-rings 30 and the upper surface of photo sheet 40.
To produce the above-mentioned "interrupted cut" slits 41, lower blades 17 each have two spaced "timing notches" 17-1 and 17-2, as shown in FIG. 4. The length of arc 45 between point A of leading timing notch 17-1 and point B of trailing timing notch 17-2 is equal to the length of an "interrupted cut" slit 41 if there is no slippage of photo sheet 40 relative to lower blade 17. The feeding of photo sheet 40 is synchronized to the times at which timing notches 17-1 and 17-2 meet upper blade 12 to produce the leading half inch margin 42A and the trailing half inch margin 42B (FIG. 2) that keep photo sheet 40 intact after the horizontal "interrupted cut" slits 41 are made.
In order that timing notches 17-1 and 17-2 become aligned with leading and trailing edge portions, respectively, of photo sheet 40 at exactly the right times, the rotation, i.e., "timing", of upper blades 12 and lower blades 17 must be precisely coordinated with the advancement of photo sheet 40. A major problem that has arisen in use of the standard Rollem Slip Stream machine is that the photo sheets 40 are frequently formed on photo paper sheets of various thicknesses, kinds of paper, and surface finishes. It has been found that such variation in thickness and kind of photo paper and the differences in "slipperiness" of the various finishes result in different amounts of slippage of photo sheet 40 with respect to the mechanism 35 which advances it in the direction of arrow 34. This disturbs the relative position or "timing" between notches 17-1 and 17-2 and the leading and trailing edges of photo sheet 40.
In order to accurately slit photo sheets of different thicknesses, kinds of material, and/or surface finishes, it has been necessary to shut down the Rollem Slip Stream machine 1, loosen a chain-driven drive clamp located on the upper drive shaft, manually advance or retard the lower notched blade in order to advance or retard the timing notches thereon, re-tighten the drive clamp, and test the results by starting up the Rollem Slip Stream machine and running a photo sheet through it. Typically, several attempts have been required to obtain the correct notch timing. This has been a very labor-intensive, time-consuming, and expensive procedure.
Consequently, there is an unmet need for a practical, economical solution to the above problems associated with varying amounts of slippage of photo sheets of various thicknesses, various kinds of paper, and various surface finishes, and especially to avoid the need to shut down operation of the Rollem Slip Stream machine and perform the time-consuming foregoing timing adjustment process.